4.19-stable review patch. If anyone has any objections, please let me know.
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commit a579121f94aba4e8bad1a121a0fad050d6925296 upstream.
In commit e53c4b598, I *tried* to teach xfs to force writeback when we fzero/fpunch right up to EOF so that if EOF is in the middle of a page, the post-EOF part of the page gets zeroed before we return to userspace. Unfortunately, I missed the part where PAGE_MASK is ~(PAGE_SIZE - 1), which means that we totally fail to zero if we're fpunching and EOF is within the first page. Worse yet, the same PAGE_MASK thinko plagues the filemap_write_and_wait_range call, so we'd initiate writeback of the entire file, which (mostly) masked the thinko.
Drop the tricky PAGE_MASK and replace it with correct usage of PAGE_SIZE and the proper rounding macros.
Fixes: e53c4b598 ("xfs: ensure post-EOF zeroing happens after zeroing part of a file") Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Reviewed-by: Dave Chinner dchinner@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Luis Chamberlain mcgrof@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/xfs/xfs_bmap_util.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 9d1e5c3a661e..211b06e4702e 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1175,9 +1175,9 @@ xfs_free_file_space( * page could be mmap'd and iomap_zero_range doesn't do that for us. * Writeback of the eof page will do this, albeit clumsily. */ - if (offset + len >= XFS_ISIZE(ip) && ((offset + len) & PAGE_MASK)) { + if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) { error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, - (offset + len) & ~PAGE_MASK, LLONG_MAX); + round_down(offset + len, PAGE_SIZE), LLONG_MAX); }
return error;